Tremblay F, Laroche R G, De Becker I
Department of Ophthalmology, Dalhousie University, Halifax, Nova Scotia, Canada.
Vision Res. 1995 Aug;35(16):2383-93. doi: 10.1016/0042-6989(95)00006-l.
Fifteen patients with the incomplete form of congenital stationary night blindness (iCSNB) were reviewed to better characterize their electroretinographic (ERG) findings in view of differential diagnosis with other retinal conditions also presenting with negative bright-flash ERG responses. In all 15 patients, in dark-adapted conditions, the bright-flash ERG response had a normal a-wave followed by a subnormal b-wave. Oscillatory potentials (OPs) observed on the ascending limb of the b-wave, although delayed in implicit time, were of large amplitude. The response to a long-wavelength stimulus showed cone-related components and some well-delineated OPs. On the other hand, the photopically elicited cone responses were strongly abnormal, with a subnormal a-wave followed by a barely recordable b-wave. No OPs could be elicited under photopic conditions. The cone related components and the OP characteristics clearly distinguish iCSNB from the complete form of CSNB and other retinal conditions presenting with minimal fundus abnormalities but with negative bright-flash ERG responses, such as found in Duchenne muscular dystrophy and Aland Island eye disease. The severely abnormal post-synaptic components in the photopic recordings contrast with the well-differentiated cone activity evoked in scotopic conditions. We propose a cone system that does not respond optimally under the normal operating range (photopic) but rather under mesopic or scotopic conditions. In spite of the severe cone-ERG deficits, visual acuity was only slightly reduced. We propose that the defect, which interferes marginally with the neuronal flow of information, lies in the structures responsible for the building of the b-wave.
回顾了15例不完全型先天性静止性夜盲（iCSNB）患者，鉴于其与其他视网膜疾病（这些疾病也表现为闪光视网膜电图（ERG）反应阴性）的鉴别诊断，以更好地描述其ERG表现。在所有15例患者中，在暗适应条件下，闪光ERG反应a波正常，随后b波异常。在b波上升支观察到的振荡电位（OPs），尽管隐含时间延迟，但振幅较大。对长波长刺激的反应显示出与视锥细胞相关的成分和一些清晰可辨的OPs。另一方面，明视诱发的视锥细胞反应严重异常，a波异常，随后b波几乎无法记录。在明视条件下无法引出OPs。视锥细胞相关成分和OP特征清楚地将iCSNB与完全型CSNB以及其他眼底异常轻微但闪光ERG反应阴性的视网膜疾病区分开来，如杜氏肌营养不良和奥兰岛眼病。明视记录中严重异常的突触后成分与暗视条件下诱发的分化良好的视锥细胞活动形成对比。我们提出一种视锥细胞系统，其在正常工作范围（明视）下反应不佳，而在中间视觉或暗视条件下反应较好。尽管视锥细胞ERG严重缺陷，但视力仅略有下降。我们认为，这种对神经元信息流有轻微干扰的缺陷，存在于负责b波形成的结构中。
